Latching and tripping mechanism.



V. S. B EAM & E. C. OTTO. LATCHING AND TRIPPING MECHANISM.

APPLICATION FILED OCT- 2- 1913.

Patented May 22, 1917.-

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UNITED STATES PATENT OFFIOEJ VICTOR S. BEAM, OF MAPLEWOOD, AND ERNEST C. OTTO, 0F ELIZABETH, NEW JERSEY,

ASSIGNOBS T0 WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A COR- PORATION OF PENNSYLVANIA.

Specification of Letters Patent.

Patented May 22, 1917.

Application filed October 2, 1913. Serial No. 792,963.

To all whom it may concern:

provements' in Latching and Tripping Mechanisms, of which the following is a specification.

Our invention consists of a latching and tripping mechanism'for such instruments or devices as are forced into a given position or condition by means of a toggle or equivalent force modifying device against an opposing force such as exerted by specially arranged springs or by the natural resiliency of the parts. With such instruments or devices, it has been the custom to construct the latching and tripping mechanism so that any particular instrument will be locked either in the underset or in the overset position of the toggle or other equivalent mechanism, but not in both such positions. With our improvement it is possible to have the instrument latched and tripped by the same mechanism, whether the toggle or its equivalent is underset or overset, that is, whether it has stopped somewhat short of or passed beyond the dead center. This results in greater flexibility in use and application of such instruments with simplicity of structure. Our invention is particularly applicable to electric circuit-breakers and we have illustrated our invention in connection with such instruments but we do not desire to have the invention limited to use with such instruments.

In the accompanying drawing Figure 1 shows our improvement embodied in a toggleoperated automatic electric circuitbreaker while Fig.2 shows the invention embodied in a circuit-breaker in which the closing mechanism consists of a cam, the other parts of the circuit-breaker being the same as in Fig. 1 but some of them are broken away in this figure. The supporting base 1 which may be of marble, slate or similar material has mounted upon its face two stationary terminals 2 and 3 with which cooperates a laminated bridging member 1.

his member 4: is carried upon an arm 5 pivoted at 6 to the bracket 7 mounted upon the base. Immediately above the stationary terminal 3 is a shunt contact 8, preferably of carbon, which cooperates with a similar contact 9 mounted upon the arm 5 through the medium-of the arm 10 to throw the con tact 9 yieldingly forward. The path of the electric current through this circuit-breaker which is shown in its closed position will be to the main stationary contact 3 from the connection of the back of the board, thence the path of the main current will be through the laminated member i to the lower main stationary terminal 2 and through another connection at the back of the board, but a small amount will also flow from the terminal 3 through the shunt contacts 8 and 9 to the lower stationary terminal and when the circuit-breaker is open the main current will be interrupted at the terminal 3 and the current will finally be broken through the shunt path, that is between contacts 8 and 9 so as to keep the resulting are away from the metallic parts of the breaker. The circuit-breaker is forced into the closed po sition by means of the handle 12 pivoted at 13 and having an inward extension 14 which together with the link 15 pivoted to the arm 5 at 16 forms a toggle joint, the two parts being pivoted to each other at 17. The circuit-breaker has been brought to the closed position by pulling down on the handle 12 and this causes the pivot 17 to follow the path 18 upward, a gradually increasing force being exerted by the toggle until it reaches the dead center position indicated by the line 19. In this position the toggle might possibly hold the circuit-breaker closed but the equilibrium would only be neutral and there would not be a positive force against which to lock the circuitbreaker closed so that the toggle must stop with its center line either 'alittle below the dead center line 19 as indicated by the line 20 or a little beyond this dead center line as indicated by the line 21. Either position willbe satisfactory so far as the electric contacts are concerned, for the position of the arm 5 carrying these contacts is not materially changed for these different positions of the toggle. A latch 22 pivoted at 23 engages an extension of the handle 24 to keep the circuit-breaker in the closed position; To trip this latch is provided a bar so v 25, also pivoted at 23, and having an adjustable pin for engaging the inner end of said latch 22. This bar has at its inner end an armature 27 which cooperates with a piece of magnetizable material 28 which partially surrounds the stationary contact 2. The attraction of this armature to the piece 28 varies with the amount of current flowing through the breaker so that the bar 26 may be moved to trip this latch by an excessive current flowing through the circuit-breaker. It may also be tripped by hand by pressing down on the knob 29.

Referring now particularly to the engagement of the latch 22 with the extension 24, it will be seen that the horizontal pin 30 carried by 24 rests in a notch formed between shoulders 31 and 32 of the latch. If, as shown in Fig. 1, the toggle is underset, that is with its center along line 20, this pin 30 will bear against shoulder 31 and hold the breaker closed but if the toggle is overset, that is if the center is along line 21, this pin will bear against shoulder 32 to hold the breaker closed. This latter position of the pin 30 is indicated in dotted lines and the position of the center line of extension 24 corresponding to positions 19, 20 and 21 of the toggle are indicated by 19, 20, and 21'. The curved line represents the path of the center of pin 30 and to insure that the circuit-breaker will be locked for either the underset or overset positions it is necessary that the shoulders 31 and 32 shall each extend above this are 33. In opening the circuit-breaker for the underset condition of the toggle shown in Fig. 1 the pin 30 will simply disengage the shoulder 31 when the outer end of the latch 22 is moved downward while when the circuitbreaker is opened from the overset condition of the toggle the shoulder 32 will force the pin 30 outward so as to bring the toggle back through the dead center position when the resiliency of the laminated member will force the circuit breaker open. The notch formed by the shoulders 31 and 32 need only be wide enough so that whenthe pin 30 comes out of engagement with one of the shoulders it will not be engaged by the other shoulder.

In Fig. 2 the corresponding parts are given the same reference letters as in Fig. 1 and the cam surface at the inner end of the part 14 is designated by the numeral 34 and this engages a roller 35 pivoted at 16 on the arm 5. In this figure 18 is the path of the center of curvature of the cam surface 34. The circuit-breaker of Fig. 2 is shown with the cam underset but the overset position and dead center positions of this cam is indicated by dotted lines.

The calibration of the circuit-breaker will depend upon the shape of the shoulders and on the latch 22 and the parts may be so arranged that this calibration is not affected by changing from the underset to the overset position of the operating mechanism, or the calibration may be made different for the two positions of the operating mechanism if desirable.

What we claim is:

1. In a circuit breaker, a contact carrying arm, an operating lever for the said arm, a toggle joint between the said lever and the said arm for forcing the said arm into either of two positions for latching, a latching device for holding it in either position when it is OK its dead-center position.

2. In a circuit breaker, a contact carrying arm, an operating lever for said arm, a toggle mechanism between the said arm and the said lever for forcing the breaker closed, and a latching device for holding the breaker closed when it is overset and underset with respect to its dead-center position.

3. In an automatic circuit breaker, a contact-carrying arm, an operating lever operatively connected to the said arm by means of a toggle mechanism that is adapted to pass beyond its dead-centerposition, a latch for holding the breaker in either the overset or underset position of the toggle, and means for tripping the said latch.

4. A latching device for a toggle operated circuit interrupter comprising a pin carried by the toggle mechanism, and a latch for engaging the said pin in either its under or overset position.

5. In a compression or energy-storing device in which the potential energy is produced by the operation of a toggle mechanism, a single means for latching the same whether the operating mechanism is overset or underset.

6. A latching device for a circuit interrupter comprising an engaging member, a pawl having a notch therein either side of which is adapted to be engaged by the said engaging member, one of the sides being so shaped as to permit the engaging member to move in the direction of its tension and the other so shaped as to force the engaging member in a direction opposed to its tension upon a predetermined movement of the pawl.

7 In a circuit interrupter, the combination with a toggle operating mechanism, of a single means for latching the toggle mechanism in either its overset or its underset position.

8. In a circuit breaker having an operating mechanism, a pin therein, and a pawl having shoulders for engaging the pin to latch the circuit breaker, said pin bearing against one of the shoulders if the operating mechanism is overset and against the other shoulder 1f the operatlng mechanism 1s underset.

9. In a circuit breaker, the combination With an operating mechanism having a pin therein, of a pawl having tWo shoulders for engaging the said pin when the operating mechanism is either overset or underset.

10. In a circuit interrupter, the combination With an operating mechanism adapted to be either overset or underset in its closed position, of a latching device adapted to secure the operating mechanism in either of its closed positions.

11. In an automatic electric circuit breaker, the combination With main and stationary contact members operated by means of a toggle mechanism, of a latch for holding the contact members in engagement in either the underset or overset condition of the toggle mechanism, and a tripping de Vice for tripping the said latch.

12. The combination with a toggle mechanism, of a single means for latching the mechanism in either its underset or its over set position.

13. The combination With relatively movable contact members and an operating mechanism therefor adapted to assume an underset or an overset position When the contact members are in engagement, of a toggle mechanism in either its underset or its overset position.

VICTOR S. BEAM. ERNEST G. OTTO. Witnesses:

THOMAS A. DEMPSEY, WILLIAM C. BROADHURST.

Copies of this patent may be obtained for five cents each, by addressing the "Commissioner of Patents,

Washington, .D. 0. 

